This application claims priority to Brazilian Application No. 10 2013 001208 4 filed Jan. 17, 2013, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
This patent application relates to an innovative constructive system of a self-ligating bracket with variable resistance to sliding, and, more specifically, a system in which by the inclusion of certain components in the structure of the bracket, either extending towards the archwire slot and/or laterally, distinct behavior of the clip or blade may be produced, and therefore in the interaction with the archwire, thereby enabling a variation in the resistance to sliding in the interface.
2. Background of the Technology
Orthodontic brackets are the main elements in a group of accessories that perform corrective action in the treatment to improve occlusion and dental positioning for the patient.
According to established orthodontic techniques of the related art, it is necessary to connect an archwire to the bracket using an elastomeric or metallic ligature tie.
In the case of brackets with tie wings (which may for example, include a pair of wings also interchangeably referred to herein as “twin wings”), the ligature must be tensioned so as to include the tie wings mesially and distally housing itself underneath the recess of the wings. This procedure, involves a selection between an elastomeric ligature or metallic ligature tie, the process being repetitive and time consuming for the professional.
Elastomeric ligature ties that securely retain the archwire inside the slot suffer degradation in the oral environment, hindering control over dental movement. This degradation causes friction and interactions of unwanted forces thereby preventing uniformity in the ligating process. Another negative point for the elastomeric ligature ties is that they accumulate organic material, allowing the formation of bacterial plaque and complicating oral hygiene.
On the other hand, metallic ligature ties, due to the vibratory forces of mastication, become loose with time, resulting in a loss of control and lack of uniformity in the ligating process. Metallic ligature ties also have sharp points, which cause them to be prone to harming the people involved and exposing professionals to infections by bacteria or viruses, such as Hepatitis B.
Therefore, in an orthodontic treatment, it is fundamental to exercise control of the forces involved in moving the arches and teeth, carried out by the conjunction of the elements involved, e.g., by the bracket, the locking mechanism and ligating the archwire, in combination with expertise from the professional involved.
In order to better illustrate the above statement, according to the characteristics of the forces of the archwires used in the beginning of treatment, an interaction of forces occurs when the archwires contact the blade or clip of the locking mechanism of the slot. During the interaction, depending on the amplitude of the movement, the arch may or may not energize the arms of the blade or clip. In this context, the force of the archwires applied at the beginning of treatment is lower, performing a function of dental movement that is more effective in a passive environment. In this situation the arms of the blade or clip should not deflect.
In the current state of the related art for this technique, some patent documents describe means of controlling the load friction and the interval of the blade or clip movement over the archwire. For example, US Patent Publ. No. 20100062387 deals with a clip for a self-ligating bracket with a projection between the labial surface of the bracket and the vestibular portion of the clip that can be turned in adjustment intervals. A screw stem or an eccentric action mechanism can be utilized as a fixation element.
The utilization of screws and other features and/or methods to limit the action range of the blade or clip leads to frequent manual adjustments, thereby undercutting one main advantage of a self-ligating bracket, e.g., that of enabling the performance of fast and easy clinical management procedures.
Other examples of such solutions are depicted in U.S. Pat. No. 6,257,883, which illustrates a constructive structure for the bracket configuration with a housing in the extremities of the clip or blade under the tie wings, enabling inhibiting of the labial displacement of the clip so as to dissipate the exceeding forces.
There remains an unmet need for a constructive system of a self-ligating bracket with variable resistance to sliding.